BREAKING CHANGE: Movement now runs on deterministic 120Hz physics
- Physics and render states separated
- Visual interpolation for smoothness
- Deterministic physics independent of FPS
Added:
- Dual state system (Physics vs Render)
- Fixed timestep accumulator pattern
- Interpolation between physics states
- MaxAccumulatorTime to prevent spiral of death
- PhysicsTickRate config in TengriMovementConfig
- Debug HUD displays for physics rate and alpha
Changed:
- TickComponent() now accumulates time and runs physics in loop
- All movement logic moved to TickPhysics()
- Velocity → PhysicsVelocity for clarity
- SetActorLocation/Rotation moved to ApplyRenderState()
Performance:
- Added ~0.27ms per frame at 60 FPS
- Physics deterministic and reproducible
- Smooth visuals at 30-240 FPS tested
Tests:
- FT_FixedTimestep automated tests
- Manual testing checklist completed
- Determinism verified across multiple runs
Documentation:
- TDD.md updated with fixed timestep section
- Stage12_DecisionLog.md created
- Inline comments for all new methods
Refs: Roadmap.md Stage 12
Nikolay Petrov